This invention relates to mechanical spacers between disks and disk clamps in disk drive systems.
Disk drives are an important data storage technology, which include several crucial components. Disk drive read-write heads directly communicate with a disk surface containing the data storage medium over a track on the disk surface. This invention involves improving the ability to position at least one read-write head over the track on the disk surface.
FIG. 1A illustrates a typical prior art high capacity disk drive 10 including actuator arm 30 with voice coil 32, actuator axis 40, suspension or head arms 50-58 with slider/head unit 60 placed among the disks 12.
FIG. 1B illustrates a typical prior art high capacity disk drive 10 with actuator 20 including actuator arm 30 with voice coil 32, actuator axis 40, head arms 50-56 and slider/head units 60-66 with all but one disk 12 removed as well as including spindle motor 80.
Since the 1980xe2x80x2s, high capacity disk drives 10 have used voice coil actuators 20-66 to position their read-write heads over specific tracks. The heads are mounted on head sliders 60-66, which float a small distance off the disk drive surface when in operation. Often there is one head per head slider for a given disk drive surface. There are usually multiple heads in a single disk drive, but for economic reasons, usually only one voice coil actuator.
Voice coil actuators are further composed of a fixed magnet actuator 20 interacting with a time varying electromagnetic field induced by voice coil 32 to provide a lever action via actuator axis 40. The lever action acts to move head arms 50-56 positioning head slider units 60-66 over specific tracks with speed and accuracy. Actuator arms 30 are often considered to include voice coil 32, actuator axis 40, head arms 50-56 and head sliders 60-66. Note that actuator arms 30 may have as few as a single head arm 50. Note also that a single head arm 52 may connect with two head sliders 62 and 64.
FIG. 2 illustrates an exploded schematic view of a disk drive 10 including disk 12 separated by spacer 84 from disk 14 as found in the prior art.
Disk drive 10 also includes a printed circuit board assembly 120, a disk drive base 100, a spindle motor 80, a disk 12, a voice coil actuator 30, a disk clamp 82 and a disk drive cover 110.
FIG. 3A illustrates a disk spacer 84 as in FIG. 2 with an emphasis on its outer surface, which is essentially cylindrical, as found in the prior art.
A spacer 84 may include screw holes, which are not relevant to the invention and will not be illustrated nor discussed hereafter.
FIG. 3B illustrates a typical prior art situation regarding the flow of air between disks 12 and 14 separated by disk spacer 84 while spinning in a disk drive.
Spindle motor 80 powers the rotating disk assembly including disks 12 and 14, as well as disk spacer 84 and disk clamp 82. To insure mechanical stability, all members of the rotating disk assembly are required to be symmetric about the axis of rotation for the assembly. This has lead prior art disk spacers 84 to have smooth cylindrical walls facing the air gap between disks 12 and 14.
The outer wall of at least disk spacer 84 is cylindrical. In many prior art disk systems, the outer walls of spindle motor 80 and disk clamp 82 are also cylindrical.
It should be noted that while the prior art disk spacers 84 address the requirements known in the prior art, there are some problems with these devices.
FIG. 3C illustrates the effect of smooth outer walls for disk spacer 84, spindle motor 80 and disk clamp 82 upon the flow of air in the air cavity around disks 12 and 14, as found in the prior art.
In each of the inner regions 140 near disk spacer 84, as well as spindle motor 80 and disk clamp 82, the inventors have found that the air is nearly stationary, particularly in region 142. This region 142 is a zone dominated by the solid body motion of the cylindrical outer wall. This region of stationary air allows particles carried in the air to adhere to the surfaces of disks 12 and/or 14. These particles cause media failures for the disk surfaces of inner regions 140 to be much higher than outside these inner regions 140. What is needed is a way of reducing particle adherence to these inner regions 140 so as to reduce data failures in these regions.
The inventors have found that by changing the outer wall shape of at least the disk spacer, the air flow of the relevant inner region is disrupted, causing particulate adhesion to be minimized. The air flow disruption acts to blow more air through the inner region, effectively moving particles away from the inner region rather than retaining these particles. The inventors call disk spacers with outer wall shapes disrupting the flow of air in the inner region, screw-type spacers. Note that the invention also relates to the outer wall of disk clamps.
Mass distribution in a screw-type spacer is symmetrical about the axis of rotation of the rotating disk assembly to which the screw-type spacer belongs. This mass distribution helps minimize mechanical vibration when the rotating disk assembly is in operation within its disk drive.
The outer wall shapes will be called blades herein. The invention includes blades of many shapes, including, but not limited to, rectangular prisms oriented with respect to the radius from the axis of rotation, as well as non-rectangular shapes such as triangular prisms providing a symmetric mass distribution for the screw-type spacer about the axis of rotation.
The invention includes not only screw-type spacers, but also the method of making disk drives using screw-type spacers and those disk drives as a product of the manufacturing process. The invention includes the method of operating the screw-type spacer to blow away particles from the inner region about the screw-type spacer and neighboring disks.
Note that a disk drive may include more than one screw-type spacer, each blowing particles away from the inner region surrounding itself.
These and other advantages of the present invention will become apparent upon reading the following detailed descriptions and studying the various figures of the drawings.